1 /*
2 * Copyright 2021-2024 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 /*
11 * This is a read only BIO filter that can be used to add BIO_tell() and
12 * BIO_seek() support to source/sink BIO's (such as a file BIO that uses stdin).
13 * It does this by caching ALL data read from the BIO source/sink into a
14 * resizable memory buffer.
15 */
16
17 #include <stdio.h>
18 #include <errno.h>
19 #include "bio_local.h"
20 #include "internal/cryptlib.h"
21
22 #define DEFAULT_BUFFER_SIZE 4096
23
24 static int readbuffer_write(BIO *h, const char *buf, int num);
25 static int readbuffer_read(BIO *h, char *buf, int size);
26 static int readbuffer_puts(BIO *h, const char *str);
27 static int readbuffer_gets(BIO *h, char *str, int size);
28 static long readbuffer_ctrl(BIO *h, int cmd, long arg1, void *arg2);
29 static int readbuffer_new(BIO *h);
30 static int readbuffer_free(BIO *data);
31 static long readbuffer_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fp);
32
33 static const BIO_METHOD methods_readbuffer = {
34 BIO_TYPE_BUFFER,
35 "readbuffer",
36 bwrite_conv,
37 readbuffer_write,
38 bread_conv,
39 readbuffer_read,
40 readbuffer_puts,
41 readbuffer_gets,
42 readbuffer_ctrl,
43 readbuffer_new,
44 readbuffer_free,
45 readbuffer_callback_ctrl,
46 };
47
BIO_f_readbuffer(void)48 const BIO_METHOD *BIO_f_readbuffer(void)
49 {
50 return &methods_readbuffer;
51 }
52
readbuffer_new(BIO * bi)53 static int readbuffer_new(BIO *bi)
54 {
55 BIO_F_BUFFER_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
56
57 if (ctx == NULL)
58 return 0;
59 ctx->ibuf_size = DEFAULT_BUFFER_SIZE;
60 ctx->ibuf = OPENSSL_zalloc(DEFAULT_BUFFER_SIZE);
61 if (ctx->ibuf == NULL) {
62 OPENSSL_free(ctx);
63 return 0;
64 }
65
66 bi->init = 1;
67 bi->ptr = (char *)ctx;
68 bi->flags = 0;
69 return 1;
70 }
71
readbuffer_free(BIO * a)72 static int readbuffer_free(BIO *a)
73 {
74 BIO_F_BUFFER_CTX *b;
75
76 if (a == NULL)
77 return 0;
78 b = (BIO_F_BUFFER_CTX *)a->ptr;
79 OPENSSL_free(b->ibuf);
80 OPENSSL_free(a->ptr);
81 a->ptr = NULL;
82 a->init = 0;
83 a->flags = 0;
84 return 1;
85 }
86
readbuffer_resize(BIO_F_BUFFER_CTX * ctx,int sz)87 static int readbuffer_resize(BIO_F_BUFFER_CTX *ctx, int sz)
88 {
89 char *tmp;
90
91 /* Figure out how many blocks are required */
92 sz += (ctx->ibuf_off + DEFAULT_BUFFER_SIZE - 1);
93 sz = DEFAULT_BUFFER_SIZE * (sz / DEFAULT_BUFFER_SIZE);
94
95 /* Resize if the buffer is not big enough */
96 if (sz > ctx->ibuf_size) {
97 tmp = OPENSSL_realloc(ctx->ibuf, sz);
98 if (tmp == NULL)
99 return 0;
100 ctx->ibuf = tmp;
101 ctx->ibuf_size = sz;
102 }
103 return 1;
104 }
105
readbuffer_read(BIO * b,char * out,int outl)106 static int readbuffer_read(BIO *b, char *out, int outl)
107 {
108 int i, num = 0;
109 BIO_F_BUFFER_CTX *ctx;
110
111 if (out == NULL || outl == 0)
112 return 0;
113 ctx = (BIO_F_BUFFER_CTX *)b->ptr;
114
115 if ((ctx == NULL) || (b->next_bio == NULL))
116 return 0;
117 BIO_clear_retry_flags(b);
118
119 for (;;) {
120 i = ctx->ibuf_len;
121 /* If there is something in the buffer just read it. */
122 if (i != 0) {
123 if (i > outl)
124 i = outl;
125 memcpy(out, &(ctx->ibuf[ctx->ibuf_off]), i);
126 ctx->ibuf_off += i;
127 ctx->ibuf_len -= i;
128 num += i;
129 /* Exit if we have read the bytes required out of the buffer */
130 if (outl == i)
131 return num;
132 outl -= i;
133 out += i;
134 }
135
136 /* Only gets here if the buffer has been consumed */
137 if (!readbuffer_resize(ctx, outl))
138 return 0;
139
140 /* Do some buffering by reading from the next bio */
141 i = BIO_read(b->next_bio, ctx->ibuf + ctx->ibuf_off, outl);
142 if (i <= 0) {
143 BIO_copy_next_retry(b);
144 if (i < 0)
145 return ((num > 0) ? num : i);
146 else
147 return num; /* i == 0 */
148 }
149 ctx->ibuf_len = i;
150 }
151 }
152
readbuffer_write(BIO * b,const char * in,int inl)153 static int readbuffer_write(BIO *b, const char *in, int inl)
154 {
155 return 0;
156 }
readbuffer_puts(BIO * b,const char * str)157 static int readbuffer_puts(BIO *b, const char *str)
158 {
159 return 0;
160 }
161
readbuffer_ctrl(BIO * b,int cmd,long num,void * ptr)162 static long readbuffer_ctrl(BIO *b, int cmd, long num, void *ptr)
163 {
164 BIO_F_BUFFER_CTX *ctx;
165 long ret = 1, sz;
166
167 ctx = (BIO_F_BUFFER_CTX *)b->ptr;
168
169 switch (cmd) {
170 case BIO_CTRL_EOF:
171 if (ctx->ibuf_len > 0)
172 return 0;
173 if (b->next_bio == NULL)
174 return 1;
175 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
176 break;
177
178 case BIO_C_FILE_SEEK:
179 case BIO_CTRL_RESET:
180 sz = ctx->ibuf_off + ctx->ibuf_len;
181 /* Assume it can only seek backwards */
182 if (num < 0 || num > sz)
183 return 0;
184 ctx->ibuf_off = num;
185 ctx->ibuf_len = sz - num;
186 break;
187
188 case BIO_C_FILE_TELL:
189 case BIO_CTRL_INFO:
190 ret = (long)ctx->ibuf_off;
191 break;
192 case BIO_CTRL_PENDING:
193 ret = (long)ctx->ibuf_len;
194 if (ret == 0) {
195 if (b->next_bio == NULL)
196 return 0;
197 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
198 }
199 break;
200 case BIO_CTRL_DUP:
201 case BIO_CTRL_FLUSH:
202 ret = 1;
203 break;
204 default:
205 ret = 0;
206 break;
207 }
208 return ret;
209 }
210
readbuffer_callback_ctrl(BIO * b,int cmd,BIO_info_cb * fp)211 static long readbuffer_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
212 {
213 if (b->next_bio == NULL)
214 return 0;
215 return BIO_callback_ctrl(b->next_bio, cmd, fp);
216 }
217
readbuffer_gets(BIO * b,char * buf,int size)218 static int readbuffer_gets(BIO *b, char *buf, int size)
219 {
220 BIO_F_BUFFER_CTX *ctx;
221 int num = 0, num_chars, found_newline;
222 char *p;
223 int i, j;
224
225 if (buf == NULL || size == 0)
226 return 0;
227 --size; /* the passed in size includes the terminator - so remove it here */
228 ctx = (BIO_F_BUFFER_CTX *)b->ptr;
229
230 if (ctx == NULL || b->next_bio == NULL)
231 return 0;
232 BIO_clear_retry_flags(b);
233
234 /* If data is already buffered then use this first */
235 if (ctx->ibuf_len > 0) {
236 p = ctx->ibuf + ctx->ibuf_off;
237 found_newline = 0;
238 for (num_chars = 0;
239 (num_chars < ctx->ibuf_len) && (num_chars < size);
240 num_chars++) {
241 *buf++ = p[num_chars];
242 if (p[num_chars] == '\n') {
243 found_newline = 1;
244 num_chars++;
245 break;
246 }
247 }
248 num += num_chars;
249 size -= num_chars;
250 ctx->ibuf_len -= num_chars;
251 ctx->ibuf_off += num_chars;
252 if (found_newline || size == 0) {
253 *buf = '\0';
254 return num;
255 }
256 }
257 /*
258 * If there is no buffered data left then read any remaining data from the
259 * next bio.
260 */
261
262 /* Resize if we have to */
263 if (!readbuffer_resize(ctx, 1 + size))
264 return 0;
265 /*
266 * Read more data from the next bio using BIO_read_ex:
267 * Note we cannot use BIO_gets() here as it does not work on a
268 * binary stream that contains 0x00. (Since strlen() will stop at
269 * any 0x00 not at the last read '\n' in a FILE bio).
270 * Also note that some applications open and close the file bio
271 * multiple times and need to read the next available block when using
272 * stdin - so we need to READ one byte at a time!
273 */
274 p = ctx->ibuf + ctx->ibuf_off;
275 for (i = 0; i < size; ++i) {
276 j = BIO_read(b->next_bio, p, 1);
277 if (j <= 0) {
278 BIO_copy_next_retry(b);
279 *buf = '\0';
280 return num > 0 ? num : j;
281 }
282 *buf++ = *p;
283 num++;
284 ctx->ibuf_off++;
285 if (*p == '\n')
286 break;
287 ++p;
288 }
289 *buf = '\0';
290 return num;
291 }
292